This invention relates generally to a disposable airway adapter for use in connection with a carbon dioxide detector, and more particularly an airway adapter which includes two optical windows and a reflector, arranged relative to each other such that infrared radiation transmitted through the first optical window is reflected by the reflector and transmitted out through the second optical window.
One of the most important aspects of critical care is the clinician's management of the patient's airway. Oral intubation, or the placement of an endotracheal or airway tube in the trachea of a patient has become a routine procedure used to maintain a clear airway in most surgical, emergency, and intensive care situations. Failure to achieve tracheal intubation may result in the airway tube being placed in the esophagus and diverting air flow from the lungs may cause patient complications or death. One common way to determine proper endotracheal tube placement is to measure the exhaled carbon dioxide concentration of the patient through the airway tube. Carbon dioxide will normally be present in the exhalation, assuming proper placement, but in most situations will not be present in gases exiting from an esophageal tube.
Carbon dioxide detectors for this purpose are known in the art. For example, U.S. Pat. No. 4,914,720 appears to be directed to a device where an emitter and detector are arranged directly across from each other in an in-line relationship. U.S. Pat. No. 5,445,160 also is directed to a portable carbon dioxide monitor wherein the light source (emitter) is placed in a disposable airway adaptor. The entire contents of U.S. Pat. No. 4,914,720 and U.S. Pat. No. 5,445,160 are hereby incorporated by reference. U.S. Pat. No. 5,445,160 provides semi-quantitative measurements of carbon dioxide concentration. Capnometers are well known in the art and can provide more accurate measurements of carbon dioxide concentration than semi-quantitative devices by utilizing more than one wavelength of light.
The greater the distance the infrared radiation travels, the greater the absorption, which results in a more accurate measurement of the concentration of the designated gas, especially at low concentrations of the designated gas. However, the prior art arrangement of the emitter and detector being in an in-line relationship does not maximize the distance the infrared radiation can travel, and therefore does not provide the best results.
A need therefore exists for a monitoring device for measuring and indicating the concentration of exhaled carbon dioxide which is durable, storable, portable, easy to use, sensitive, reliable, safe, inexpensive, clean, and disposable.